Why do I have more vivid dreams when I nap?

[buttercup]

I noticed I tend to have more vivid dreams or lucid dreams when I sleep at a time that isn't usual for me or take a nap. Why is this?

[ButterflyWoman]

Shorter sleep cycle, so you wake much closer to the period in which you experience REM sleep. You're not actually having more vivid dreams, necessarily, but much clearer recall. (It happens to me, too, FWIW.)